Hinged-latch needle for knitting machines



June 1964 P. B. COUSTE ETAL HINGED-LATCH NEEDLE FOR KNITTING MACHINES Filed Feb. 17, 1961 f FIG: 3

FIG?

FIG: 4

United States Patent 3,137,340 HINGED-LATCH NEEDLE FOR KNITTING MACHINES Pierre Bernard Coust, Le Moulinet, Pont Sainte- Marie, France, and Robert Trenteseaux, 11 Rond Point du ler Mai, and Jacques Pallencher, 48 Rue Beauregard, both of Troyes, France 7 Filed Feb. 17, 1961, Ser. No. 89,978 Claims priority, application France July 25, 1960 1 Claim. (Cl. 1635) Hinged-latch needles for knitting machines comprise, as a rule, in the vicinity of their butts a slot carrying between its two sides the hinge pin of the latch which closes or opens the access to the needle butt according to its position.

In general, this hinge pin consists of a cylindrical threaded trunnion having formed at either end, after its assembly, a head, the two heads of each hinge pin being riveted in opposite tapered or countersunk recesses formed in the outer faces of each side, these recesses being coaxial with the tapped holes previously engaged by the latch-carrying hinge pin.

Knitting machines or hosiery needles have also been proposed wherein the latches comprise trunnionsformed integrally therewith and introduced in slots formed in the sides of the needle, after these sides have resiliently been moved apart from each other.

Now, notably in modern knitting machines operating at very high speeds, for example of the order of 16 beats per second, the slightest deflection of the latch hingle pin during the operation of the machine will cause defects to appear in the knitted product and the needle must be thrown away; however, these deflections cannot be avoided with existing latch needles since a sufficient play must be reserved during their manufacture to permit the mounting of the latches, and this play increases gradually until it becomes abnormally large after a more or lms long period of operation, due to the efforts to which these pins are subjected.

With the latch needle according to this invention these inconveniences are avoided; to this end, it is characterized in that the latch hinge pin consists of a cylindrical portion on which the latch is mounted for free rotation, this cylindrical portion having cylindrical side extensions of slightly smaller diameter which are mounted for loose rotation in holes formed to this end through the sides of the needle slot provided for mounting the needle latch.

Due to the loose mounting of the latch pin in the needle sides and of the latch on the needle, the mechanical wear is distributed throughout the peripheral surfaces of the different bores; therefore, this wear occurs at a slower rate and since it is not attended by any ovalization it is less objectionable.

The latch pin may be manufactured notably from a suitable plastic having a resistance to wear superior to that of the steel, such as nylon or like material; it is an additional advantage of the use of these modern plastics to have the possibility of reducing the clearance to a very low value, of the order of half the play usually tolerated in conventional-type needles.

This result is obtained according to this invention by providing a method of manufacturing hosiery or like needles which is characterized in that the plastic material constituting the latch pin is injected into the holes of the sides of the slot formed in the needle, and at the same time into the latch hole, the latter having been properly- Patented June 16, 1964 step, the sides are released and, due to their inherent elasticity, they resume their initial position, the plastic material filling completely the three'orifices, thus ensuring a perfect centering; the minimum play necessary for the proper operation of the latch, between the latch and the hinge pin, results from the shrinking of the plastic as it cools downto room temperature, thus permitting a very smooth operation of the latch; the hole formed through the latch is slightly greater than thoseformed through the sides of the needle slot, as already explained hereinabove, so that the relevant portion of, the hinge pin, by having similarly a slightly greater diameter, is retained between the aforesaid two sides. v

In order to afford a clearer understanding'of, this invention and of the manner in which the same may be'carried out in practice, "reference willnow be made to the accompanying drawing illustrating diagrammatically a typical embodiment of the invention. In. the drawing:

FIGURE 1 is a side. elevational view of a needle;

FIGURE 2 is a cross section taken upon the line II-II of FIG. 1, and showing on a larger scale the metal parts before the injection of the hinge pin;

FIGURE 3 is a similar view taken during the injection step; and

FIGURE 4 is a similarview taken after the injection step andwiththe hinge pin shrunk in position.

In the drawing, the needle 1 comprises in the vicinity of its hook, or butt 2 a hinge pin 3 on which a latch 4 is pivotablly mounted between two sides 5 and 6.

To this end, holes 7, 8 and 9 are formed through the side 5, latch 4 and side 6, the diameter of the latch hole 8 being slightly greater than those ofholes 7 and 9 of sides 5 and 6, respectively.

To form by injection of a suitable plastic material the hinge pin on which the latch 4 is to subsequently pivot in the needle, the two sides 5 and 6 are pressed toward each other, as shown in FIG. 3, after the holes in the sides 5, 6 and latch '4 have been strictly aligned with each other; then the plastic material is injected from the nozzle 10 through the three coaxial orifices and since no play or gap is left between the sides 5, 6 and latch 4, the plastic cannot leak in between the parts and remains concentrated inside these orifices; upon completion of the injection step proper the sides 5 and 6 are released and,

due to their inherent elasticity they resume their initial position as shown in FIG. 4, so as to leave a moderate side play permitting the pivoting movements of the latch 4; When the plastic material has cooled down to room temperature, due to the shrinking produced therein, a slight play is also obtained between the two portions 12 and 13 of smaller diameter of pin 3 and the latch 4, on the one hand, and between the relevant holes 7 and 9 of sides 5 and 6, as well as between its intermediate portion 11 of slightly greater diameter and the corresponding hole 8 in the latch 4; this very slight play permits a very smooth pivoting of the latch about the hinge pin 8.

It is another advantage of the latch needle thus ob- ,tained that the outer edges 14 and 15 of the hinge pin,

5 and 6, so that these ends will not catch the yarn during the operation of the needle in the knitting loom.

Although the present invention has been described in conjunction with apreferred embodiment, it is to be understood that modifications and variations may be resorted to Without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claim.

What we claim is':

A method of manufacturing a latch needle having a i latch pivoted about a pin extending transversely to its mounting slot, for knitting machines, wherein said pin consists of a cylindrical portion on which said latch is loosely mounted, said cylindrical portion having opposite lateral extensions also of cylindrical configuration but of smaller diameter which are loosely mounted in turn in holes formed to this end in the flanges of the mounting slot of the needle latch, which method consists inrdisposing the latch hole in alignment with said flange holes, clamping said flanges against the latch to eliminate any clearance therebetween injecting heated plastic material intojthe thus aligned holes and, when said injection is completed, releasing said flanges and allowing the thus injected'plastic material to set by cooling so that the flanges, due to their inherent elasticity, resume automatically their initial position, the plastic material filling completely the three aligned holes ensure a perfect centering, and the shrinking of the plastic material as it cools down the room temperature provides automatically the play necessary for the proper operation of the latch between said hinge-pin and said flanges and between said latch and said hinge pin.

References Cited in the file of this patent UNITED STATES PATENTS 531,023 Dodge Dec. 18, 1894 743,152 Currier Nov. 3, 1903 1,928,964 Currier Oct. 3, 1933 2,246,086 Austin June 17,1941 2,352,347 Scranton June27, 1944 2,711,218 VitouX June 21, 1955 r 2,954,992 Baker Oct. 4, 1960 FOREIGN PATENTS 319,757 Italy July. 19, 1934 394,631 Great Britain June 29, 1933 502,064 Italy Feb. 4, 

